What is the waiting period for a woman obligated to observe 'Iddah by Quru' (menstrual periods)?

Primary text

The waiting period for every woman observing 'Iddah due to separation during life or due to consummation outside of marriage, provided she is capable of menstruation (Dhat Quru'), is measured by three Quru'. The evidence is the verse: {Divorced women shall observe for themselves a waiting period of three periods} (Quran 2:228).